Spindle motor

Abstract

A spindle motor may include: a sleeve rotatably supporting a shaft; a rotor coupled to the shaft and rotating together therewith; and a base member fixedly coupled to the sleeve, wherein the base member includes a plurality of penetration holes formed therein so as to penetrate therethrough, and a magnetic material is inserted into at least one of the plurality of penetration holes, and non-magnetic materials are inserted into the remaining penetration holes.

What is claimed is: 
     
         1 . A spindle motor comprising:
 a sleeve rotatably supporting a shaft;   a rotor coupled to the shaft and rotating together therewith; and   a base member fixedly coupled to the sleeve,   wherein the base member includes a plurality of penetration holes formed therein so as to penetrate therethrough, and   a magnetic material is inserted into at least one of the plurality of penetration holes, and non-magnetic materials are inserted into the remaining penetration holes.   
     
     
         2 . The spindle motor of  claim 1 , wherein the base member is formed by plastically deforming a steel sheet. 
     
     
         3 . The spindle motor of  claim 1 , wherein the penetration holes partially protrude from an upper surface of the base member. 
     
     
         4 . The spindle motor of  claim 1 , wherein the rotor has a magnet mounted on an inner peripheral surface thereof, and
 the magnetic material is disposed in a position corresponding to that of the magnet.   
     
     
         5 . The spindle motor of  claim 1 , wherein the magnetic material is disposed in a position corresponding to a portion of the rotor inclined in an upward axial direction. 
     
     
         6 . A spindle motor comprising:
 a sleeve rotatably supporting a shaft;   a rotor coupled to the shaft, rotating together therewith, and having a magnet mounted on an inner peripheral surface thereof; and   a base member fixedly coupled to the sleeve,   wherein the base member is provided with a magnetic material to generate asymmetric pulling force between the magnetic material and the magnet.   
     
     
         7 . The spindle motor of  claim 6 , wherein the base member includes a plurality of insertion grooves formed therein, and the magnetic material is inserted into at least one of the plurality of insertion grooves. 
     
     
         8 . The spindle motor of  claim 7 , wherein the insertion grooves are recessed from a lower surface of the base member toward an upper surface of the base member. 
     
     
         9 . The spindle motor of  claim 7 , wherein non-magnetic materials are inserted into the insertion grooves other than the insertion groove into which the magnetic material is inserted among the plurality of insertion grooves. 
     
     
         10 . The spindle motor of  claim 6 , wherein the magnetic material is disposed in a position corresponding to that of the magnet. 
     
     
         11 . The spindle motor of  claim 6 , wherein the magnetic material is disposed in a position corresponding to a portion of the rotor inclined in an upward axial direction.